Compost is compost and mulch is mulch. Mulch is something you put on the ground surface to control weeds, retain moisture, etc.

Doubtful you'll find any info on this product online. As with most compost products, it's probably made regionally with ingredients available at that time. Supply streams vary seasonally and they compost what they have available.

Several reasons why this could look white. If it's high in lime or other salts, and the moisture has dried out of it, it could just be that. Or it's possible a microorganism (such as a fungus) took off and grew after it was in the bag. Most fungi are not harmful to plants and are actually an integral part of the soil food web.

If it's dry, moisten some in a bucket, let it sit to get moist through, and see what it looks and smells like. If it smells OK (earthy) and not rotten, it's probably OK to use.

You could post a picture if you want us to take a look.

It's hard to over-compost so your bed will probably be fine. Once you get a good organic matter level, usually 1/2"-1" of compost per season is enough to maintain.

Do you have a compost pile? You could dump it on there if you were concerned, let it "recook".

Compost is compost and mulch is mulch .... some of us mulch with compost.

Compost and mulch are both CARBON in different states of decomposition.

Coarse, raw wood/bark mulch will have easily identifiable bits, and will tie up nitrogen resources, and so is appropriate as a surface-applied broadcast weed-barrier soil-builder. It will be some kind of shade of brown. It will slowly decompose and be appropriately pulled down into the mineral soil by microbes and worms.

Compost is carbon whose cellulose/lignin chains have broken down into more readily usable bits for soil biota. It generally won't mess up your soil chemistry if mixed into the root zone. It should have a very dark color (pretty much black). It's not "fertilizer", but it does act more like food for your plants, and if you "mulch with compost" you are quite possibly feeding the weeds as much as your crop plants.

Compost shouldn't look like gray dust, though fungal/bacterial bodies could cause something like this. Possibly because the material has been contained inside a plastic bag, I could imagine everything becoming "moldy"....

Tox and lisa have good advice.

Good luck!

" Compost is compost and mulch is mulch .... some of us mulch with compost."

Indeed. I was trying to keep things simple for the OP, and sometimes that results in leaving out complexities. :-D

One (remote) possibility. If it has a lot of composted steer manure then the ashy gray may have be salts dried up on the surfaces of the particles. Steer manure is very cheap composted manure (but not necessarily cheap compost) and it is loaded with sodium chloride salt from feedlot management practices. If so, it can be managed by not using a lot of it in one spot and/or by flushing with rain or hose water to leach down the salt.

Compost will never have a grey ash appearance, unless someone has added ash to the mix in quite large quantities. This is not something I would put down on my garden, although I might spread it, thinly, on my lawn.

kimmq is kimmsr

Tropitango, what did you want to do with this compost? If it were going on a flower bed, I'd use it.

You're a little confused about the difference between mulch and compost. Mulch incorporated into the soil ceases to be mulch; it becomes an amendment. Mulch is always an undisturbed, surface covering which is used for weed suppression and for moisture trapping or to keep soil cool. Those of us who use compost as a mulch do so because it feeds our garden and we find it attractive.

The reason people get confused about mulch is because they associate it with wood product mulches, but I prefer more quickly nourishing mulches such as a compost mulch or a leaf mould mulch or newspaper and hay.

It is just molded compost, due to it being inside a plastic bag without being dry. You can use it right now, but if you feel strongly about cosmetics, pile it somewhere for a week until the anaerobic mold disappears.

Some are confused about what is mulch and what is not.

Mulch is anything that is placed on the soils surface to 1. aid in control of unwanted plant growth, 2. aid in soil moisture conservation, 3. aid in moderating soil temperatures, and 4. adding organic matter to the soil over time.

Compost is a product made by mixing organic matter in such a way that certain microscopic critters convert that material into something plants can use. Compost can be mulch, depending on how it is used.

kimmq is kimmsr

I would argue that it's not an efficient use of resources to use compost as mulch.

All carbon locked in the matrices of living tissues follows a gradient. Just as water always runs down-hill, carbon always seeks to be released back into the atmosphere as CO2. A much larger portion of your surface-applied carbon will be lost to photo-degradation and microbial respiration. Much of it will primarily benefit freshly germinated weed-seeds. Yes, some of it will get pulled down by the critters, but we're talking relative efficiency here. Mineral soil acts as a substrate for the carbon to cling to; it "wets" the surface of the soil particles/colloids, so the more you can incorporate it into the mineral soil, the longer it will take to pool&cascade up the chain of consumer organisms, back to its ultimate source/sink, the atmosphere. Additionally, it is plant roots which uptake CO2, so more readily available carbon *in the root-zone* is more beneficial to your plants.

Mulch should ideally be high C:N ratio. This helps it last longer in the service of limiting light required to germinate weed seed, suppressing weed growth, cultivating microbe populations, and moderating temperature/moisture fluctuations.

Considering the amount of time/energy required to produce/distribute quality compost, I think it wise to treat it with some amount of thoughtful reverence.

Cheers,
Shane

I agree. I'll throw in one twist though, I've used compost directly on top of the soil as the bottom layer of a multi-layer nutritional mulch, say on tomatoes after planting. Usually it's half-digested compost. On top of that would be shredded leaves, leaf/grass clipping mix, straw, etc. Only when I can't dig it in, and the compost always goes on the soil surface so the worms can begin incorporating it. Mulch goes on top to do what mulch does.

But generally speaking I agree compost isn't really a mulch.